This invention relates to blow molded sealed aseptic bottles, a method for blow molding sealed aseptic bottles and an apparatus for sealing blow molding aseptic bottles.
Conventional aseptic bottles are blow molded using high pressure sterile air. The high pressure sterile air is vented and then the bottles are either sealed in the mold or the molded bottles are filled and sealed immediately after being molded so as to assure the sterility of the bottles and their contents. Often it is not practical to fill freshly molded sterile bottles. For example, there may be a time interval or travel distance between the blow molding operation and the filling operation.
Sealing blow molded aseptic bottles in the mold has met with limited success, requiring complicated tooling and processing and resulting in bottles that are fragile and prone to failure during transportation/storage prior to filling. Thus, there is a need for a simplified seal for aseptic bottles that is more rugged and employs less complex tooling. A rugged, simplified seal for aseptic bottles will assure that it can be stored for a sufficient period of time without damage to the seal or distortion to the aseptic bottle.
In achieving the above objectives and overcoming the limitations of the prior art, the present invention provides a sealing apparatus for blow molded bottles which includes a pair of mold halves that define a bottle cavity, first and second dome cavities and a passageway connecting the dome cavities. A sealing is removably mounted through one of the mold halves and is movable so as to be extended into the passageway. The tool includes a pair of spaced apart blades formed on its distal end. In a retracted position, the tool and its blades are substantially withdrawn from the passageway. In an extended position, the blades of the tool extend partway across the passageway to compress a portion of a blow molded parison therein and form a seal in which the vestiges of the pinch line are eliminated. In the seal achieved with the present invention, the two layers of the polymeric material become molecularly joined forming what is referred to herein as a molecular seal.
In another aspect, the present invention provides a bottle which includes a body portion formed with a first dome connected to a second dome by a collapsed passageway. The collapsed passageway forms a seal having one side of the passageway displaced laterally against the opposing side, thereby being collapsed, and further having defined therein, a pair of adjacent indentations in the thermoplastic resin.
In its final aspect, the present invention provides a method for forming a sealed, unfilled hollow aseptic container from a parison of thermoplastic material. The method includes the steps of introducing a molten parison between a pair of open mold halves, closing the mold halves to capture the parison in a mold cavity having the shape of a container; flowing pressurized air into the interior of the captured parison to expand the walls of the parison against the mold cavity thereby forming an expanded parison in the shape of the mold cavity; reducing the pressure within the expanded parison; and collapsing a portion of the expanded parison and forming at least one molecular seal in the collapsed portion.